18.1 Fruits 823Fig. 18.4.Chemical structures of flavonoids
Flavanols (Faol), Anthocyanidines (Acn), Flavanones
(Faon), Flavones (Fon), Flavonols (Fool), Isoflavones
(Ifon, cf. 16.2.9). R: H, OH or OCH 3
a nutritional and physiological viewpoint. Up
to now, however, unambiguous evidence of
a health-building effect is lacking (literature
till 2006). The phenolic compounds contribute
to the color and taste of many types of fruit. In
processing, they can cause discoloration by the
formation of metal complexes and turbidity by
complexation of proteins. Table 18.15 shows the
polyphenol content of foods, which is strongly
dependent on the variety, climate and degree of
ripeness, among other factors. For instance, their
content in apples varies from 1.3g/kg (Golden
Delicious)to6g/kg (Jeanne Renard) and can
even rise to 10 g/kg in this variety.
18.1.2.5.1 Hydroxycinammic Acids,
Hydroxycoumarins
and Hydroxybenzoic Acids
p-Coumaric (I), ferulic (II), caffeic (III) and
sinapic (IV) acids are widespread in fruits and
vegetables.
These hydroxycinnamic acids are present
mainly as derivatives. The most common are
Table 18.15.Polyphenol content of foodsCompounda Food ContentbHydroxybenzoic Blackberries 80–270
acids (Hba) Raspberries 60–100
Black currants 40–130
Strawberries 20–90
Hydroxycinammic Bilberries 2000–2200
acids (Hca) Kiwi 600–1000
Cherry 180–1150
Plum 140–1140
Apple 50–600
Pear 15–600
Aubergine 600–660
Artichoke 450
Chicory 200–500
Potato 100–190
Flavanolsc Apricot 100–250
(monomer) (Faol) Cherry 50–250
Grape 30–175
Peach 50–140
Blackberry 130
Apple 20–120
Anthocyans Blackberry 1000–4000
(Acn-glycoside) Black currant 1300–4000
Bilberry 250–5000
Red grape 300–7500
Cherry 350–4500
Rhubarb 2000
Strawberry 150–750
Plum 20–250
Red cabbage 250
Flavanonesc Orange (juice) 215–685
(Faon) Grapefruit (juice) 100–650
Lemon (juice) 50–300
Flavonesc Parsley 240–1850
(Fon) Celery 20–140
Flavonolsc Bilberry 30–160
(Fool) Black currant 30–70
Apricot 25–50
Apple 20–40
Red grape 15–40
Kale 300–600
Leek 30–225
Broccoli 40–100
Bean, green 10–50
Tomato 2–15
aThe numbers and abbreviations refer to the formulas
in Fig. 18.5 and 18.6.
bValues in mg/kg fresh weight or mg/l juice.
cConcentration of the aglycone.